Fixing device for lower stage members and fluid control device equipped with fixing device

ABSTRACT

Provided are a fixing device for a lower-stage member which facilitates a leveling operation for making upper surfaces of lower-stage members coplanar, and can further enhance a vibration absorbing effect generated by an elastic member, and a fluid control device which includes the fixing device. A fixing device for a lower-stage member is configured such that respective lower-stage members ( 2 ) are fixed once and, thereafter, a desired lower-stage member ( 2 ) is moved upwardly against an elastic force ( 21 ) so as to finely adjust positions of upper surfaces of a plurality of lower-stage members ( 2 ). The elastic member ( 21 ) is formed of an annular body made of rubber or a synthetic resin. A cutout ( 21   a,    21   b ) which imparts the elastic deformation by bending when a force in the vertical direction is applied to the elastic member ( 21 ) is formed on an upper portion and a lower portion of an inner peripheral surface of the elastic member ( 21 ).

TECHNICAL FIELD

The present invention relates to a fixing device which is used in afluid control device assembled in such a manner that a plurality ofjoints (block joints) are fixed to a support member, and a fluid controlunit is fixed in a straddling manner over these joints, and moreparticularly to a fixing device which fixes the block joint (lower-stagemember) which is arranged between a support member and the fluid controlunit (upper-stage member) to the support member, and a fluid controldevice equipped with the fixing device.

BACKGROUND ART

Patent literature 1 discloses a fixing device shown in FIG. 7 as afixing device for a lower-stage member to which the present invention isalso directed.

In FIG. 7, two block joints (51) are mounted on a support member (52),and a fluid control unit (not shown in the drawing) which constitutes anupper-stage is mounted in a straddling manner over both joints (51). Ineach block joint (51), a bolt insertion hole (54) through which a jointfixing bolt (53) passes at the time of mounting the block joint (51) onthe support member (52) is formed. In the support member (52), athreaded hole (55) used at the time of mounting the block joint (51) onthe support member (52) is formed.

The bolt insertion hole (54) formed in each block joint (51) is formedof a large-diameter portion (54 a) having a diameter larger than adiameter of a bolt head portion (53 a) and a small-diameter portion (54b) which is contiguously formed with the large-diameter portion (54 a)byway of a stepped portion (54 c) and has a diameter between thediameter of the bolt head portion (53 a) and a diameter of a bolt shaftportion (53 b).

A cylindrical spacer (56) which has a lower end thereof received by thesupport member (52) and an upper end thereof disposed in thelarge-diameter portion (54 a) is fitted in the small-diameter portion(54 b) of the bolt insertion hole (54). The spacer (56) has an innerdiameter larger than a diameter of the bolt shaft portion (53 b) and anouter diameter smaller than the diameter of the bolt head portion (53a). The shaft portion (53 b) of the joint fixing bolt (53) is fittedinto the spacer (56) and the head portion (53 a) is received by an upperend surface of the spacer (56). The spacer (56) is provided for defininga fastening amount of the joint fixing bolt (53). The spacer (56) isformed such that when the joint fixing bolt (53) is made to pass throughthe bolt insertion hole (54) and is threaded into the threaded hole (55)formed in the support member (52), the spacer (56) is made to stretchbetween the bolt head portion (53 a) of the joint fixing bolt (53) andthe support member (52) thus stopping the further fastening of the jointfixing bolt (53).

An annular rubber washer (57) having an outer diameter approximatelyequal to the diameter of the head portion (53 a) of the joint fixingbolt (53) is fitted on an upper end portion of the spacer (56). Therubber washer (57) is sandwiched between the head portion (53 a) of thejoint fixing bolt (53) and the stepped portion (54 c) of the boltinsertion hole (54). A length of the rubber washer (57) in the verticaldirection is set such that a compressive force is applied to the rubberwasher (57) in a fastening completion state of the joint fixing bolt(53). Accordingly, both joints (51) are biased in the direction towardthe support member (52) by the rubber washer (57).

In such a fixing device for a lower-stage member, the rubber washer (57)has elasticity and hence, the rubber washer (57) can be further deformedby compression. Accordingly, when upper surfaces of both joints (51) arenot coplanar, one joint (51) having an upper surface lower than an uppersurface of the other joint (51) can be moved upwardly.

That is, the fixing device for a lower-stage member is configured suchthat the respective lower-stage members (51) are fixed once and,thereafter, the desired lower-stage member (51) is moved upwardlyagainst an elastic force of the rubber washer (57) so as to finelyadjust positions of upper surfaces of a plurality of lower-stage members(51). Due to such constitution, the upper-stage members (51) can beeasily mounted and, at the same time, it is possible to apply a properamount of pressing force to all seal portions interposed between thelower-stage members (51) and the upper-stage members so that sealingproperty can be ensured. Patent literature 1 exemplifies the rubberwasher (57) having a rectangular cross section as the elastic member.

CITATION LIST Patent Literature

PTL 1: Japanese Patent 3774800

SUMMARY OF INVENTION Technical Problem

According to the fixing device for a lower-stage member described in theabove-mentioned patent literature 1, when the bolt for fixing thelower-stage member is fastened, the spacer is held between the bolt headportion and the support member. At this point of time, the elasticmember biases each lower-stage member toward the support member so thateach lower-stage member has no play. On the other hand, by elasticallydeforming the elastic member by compression, the lower-stage memberhaving a lower upper surface is moved in the direction away from thesupport member and hence, upper surfaces of the lower-stage members canbe made coplanar. Accordingly, the fixing device has an advantage thatmounting of the upper-stage member on the lower-stage member can beperformed easily. Further, the elastic member absorbs vibrations andhence, the fixing device is also advantageous with respect to a pointthat the bolt which is properly fastened once is prevented from beingloosened due to vibrations or the like.

However, the elastic member having a rectangular cross section exhibitsa limited compression elastic deformation amount and hence, the elasticmember has a drawback that it is difficult to move upper surfaces of thelower-stage members to a coplanar plane at the time of performing thefine adjustment (leveling) of upper surface positions of the pluralityof lower-stage members.

It is an object of the present invention to provide a fixing device fora lower-stage member which facilitates a leveling operation for makingupper surfaces of lower-stage members coplanar, and can further enhancea vibration absorbing effect generated by an elastic member as well as afluid control device which includes the fixing device.

Solution to Problem

A fixing device for a lower-stage member according to the presentinvention is a device for fixing a lower-stage member arranged between asupport member and an upper-stage member and provided with a boltinsertion hole to the support member by a bolt, wherein the boltinsertion hole formed in the lower-stage member is formed of alarge-diameter portion having a diameter larger than a diameter of abolt head portion and a small-diameter portion which is contiguouslyformed with the large-diameter portion below the large-diameter portionby way of a stepped portion and has an intermediate diameter between thediameter of the bolt head portion and a diameter of a bolt shaftportion, a cylindrical spacer which has an inner diameter larger thanthe diameter of the bolt shaft portion and has a lower end thereofreceived by the support member and an upper end thereof disposed in theinside of the large-diameter portion is fitted into the small-diameterportion of the bolt insertion hole, and an elastic member which biasesthe lower-stage member toward the support member is interposed betweenthe bolt head portion and the stepped portion, wherein a cutout whichallows the elastic member to be elastically deformed by bending when aforce in the vertical direction is applied to the elastic member isformed at at least one place among an outer peripheral surface, an innerperipheral surface, an upper surface and a lower surface of the elasticmember.

Although a cross-sectional shape of the elastic member before the cutoutis formed may be a rectangular shape, a circular shape (including anoblong shape and an elliptical shape), a polygonal shape or the like,the cross-sectional shape of the elastic member may preferably be anoctagonal shape which is formed by cutting four corners of a rectangularshape (a rectangular shape elongated in the vertical direction). Due tosuch a cross-sectional shape, the elastic member is considered as amember which has an upper surface brought into contact with a lowersurface of the bolt head portion or a lower surface of a flange of thespacer, a lower surface brought into contact with the stepped portion ofthe bolt insertion hole, an outer peripheral surface brought intocontact with a circumferential surface of the large diameter portion ofthe bolt insertion hole, and an inner peripheral surface brought intocontact with an outer peripheral surface of the spacer, and forms atleast one cutout for forming a recessed portion on at least one surfaceamong the upper surface, the lower surface, the outer peripheral surfaceand the inner peripheral surface.

The elastic member may preferably be formed of an annular body made ofrubber or a synthetic resin.

The elastic member enables the upward movement of the lower-stage memberdue to the deformation thereof. In a fixing device which uses an elasticmember capable of performing only deformation by compression, a movableamount of the lower-stage member in the upward direction is limited. Byenabling the elastic member to perform the elastic deformation bybending, the movement of the lower-stage member in the upward directioncan be performed with a small amount of force and hence, a levelingoperation of making upper surfaces of the lower-stage members coplanarcan be performed easily. Further, vibrations can be also absorbed due tothe elastic deformation of the elastic member.

The spacer may have no flange (cylindrical body) or may have a flange onan upper end portion thereof. When the spacer has no flange, the elasticbody is arranged between a lower surface of the head portion of the boltand the stepped portion. When the spacer has a flange, the elastic bodyis arranged between a lower surface of the flange of the spacer and thestepped portion. The elastic member may preferably be arranged between alower surface of the flange formed on the upper end portion of thespacer and the stepped portion.

A cross-sectional shape of the cutout may be an approximatelyrectangular shape, for example. However, the cross-sectional shape ofthe cutout is not limited to such a shape, and may be a triangular shapeor an arcuate shape.

The cutout may be formed on two portions, that is, an upper portion anda lower portion of an inner peripheral surface or an outer peripheralsurface of the elastic member respectively, for example (thecross-sectional shape being an approximately lateral T shape).

The cutout may be formed on two portions of the elastic member in totalsuch that one cutout is formed on a vertical center portion of the innerperipheral surface and a vertical center portion of the outer peripheralsurface of the elastic member respectively (cross-sectional shape beingan approximately I shape or an approximately Z shape).

The cutout may be formed on one portion of a vertical center portion ofan inner peripheral surface or an outer peripheral surface of theelastic member (cross-sectional shape being an approximately C shape oran approximately lateral U shape).

The cutout maybe formed on three portions in total, that is, on an upperportion, on a lower portion and on a center portion of an innerperipheral surface or an outer peripheral surface of the elastic memberrespectively (cross-sectional shape being approximately lateralinverse-U shape).

The cutout may be formed on four portions in total, that is, verticalcenter portions of an inner peripheral surface and on an outerperipheral surface of the elastic member and on center portions of anupper surface and a lower surface of the elastic member respectively.

The cutout may not be limited to the above-mentioned cross-sectionalshapes, and the cross-sectional shape of the cutout can be variouslychanged provided that the cutout imparts an action which enables theelastic member to be deformed elastically by bending when a force in thevertical direction is applied.

A fluid control device according to the present invention is a fluidcontrol device which includes: a plurality of block joints in each ofwhich a fluid path opening upward is formed; a plurality of fluidcontrol units in each of which a fluid path communicated with the fluidpath of the block joint and opening downward is formed; a plurality ofseal portions which are interposed on abutting surfaces between thefluid paths of the block joints and the fluid paths of the fluid controlunits; a support member for supporting the plurality of block joints; aplurality of bolts for mounting the respective block joints to thesupport member; and a plurality of bolts for mounting the respectivefluid control units to the block joints, wherein the block jointconstitutes a lower-stage member, and the block joint is mounted on thesupport member by any one of the above-mentioned fixing devices for alower-stage member.

In this specification, “vertical” means “vertical” in the drawings.However, this “vertical” is used for the sake of convenience. The fixingdevice and the fluid control device may also be installed on ahorizontal plane in an up-side-down manner or on a vertical planebesides the installation on a horizontal plane in a state shown in thedrawings.

Advantageous Effects of Invention

According to the fixing device for a lower-stage member of the presentinvention, the elastic member is formed of an annular body made ofrubber or a synthetic resin, and a cutout which enables the elasticmember to be elastically deformed by bending when a force is applied inthe vertical direction is formed on at least one among an outerperipheral surface, an inner peripheral surface, an upper surface and alower surface of the elastic member. Accordingly, compared to a fixingdevice which uses an elastic member which is deformable only bycompression, the movement of the lower-stage member in the verticaldirection can be performed with a small amount of force and hence, aleveling operation for making upper surfaces of the lower-stage memberscoplanar can be performed easily. Further, when vibrations are appliedto the lower stage member, the elastic member is elastically deformed soas to absorb vibrations and hence, a vibration absorbing effect of adevice (for example, a fluid control device) which uses the fixingdevice for a lower-stage member of the present invention can beenhanced.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a side view with a part broken away showing a fluid controldevice of a first embodiment where a fixing device for a lower-stagemember according to the present invention is used.

FIG. 2 is an enlarged cross-sectional view of an essential part of thefixing device for a lower-stage member according to the presentinvention.

FIG. 3(A) is a view showing a state where the lower-stage member ismoved upward from a state shown in FIG. 2, and FIG. 3(B) is a viewshowing a state of a conventional product corresponding to the stateshown in FIG. 3(A).

FIG. 4(A), FIG. 4(B), FIG. 4(C), and FIG. 4(D) are cross-sectional viewsshowing examples of elastic members which can be used in the fixingdevice for a lower-stage member according to the present invention.

FIG. 5(A), FIG. 5(B) and FIG. 5(C) are cross-sectional views showingother examples of the elastic members which can be used in the fixingdevice for a lower-stage member of the present invention.

FIG. 6(A) and FIG. 6(B) are views for explaining a leveling function ofthe fixing device for a lower-stage member.

FIG. 7 is a side cross-sectional view showing a conventional fixingdevice for a lower-stage member.

REFERENCE SIGNS LIST

-   (2),(3): block joint (lower-stage member)-   (4), (5), (6), (7): fluid control unit (upper-stage member)-   (9): support member-   (10): bolt-   (10 a): bolt head portion-   (11): bolt insertion hole-   (11 a): large-diameter portion-   (10 b): bolt shaft portion-   (11 b): small-diameter portion-   (11 c): stepped portion-   (12): spacer-   (21), (22), (23), (24), (25), (26), (27): elastic member-   (21 a), (21 b), (22 a), (22 b), (23 a), (23 b), (24 a), (24 b), (25    a), (26 a), (26 b), (26 c), (27 a), (27 b), (27 c), (27 d): cutout

DESCRIPTION OF EMBODIMENTS

An embodiment of the present invention is explained in conjunction withdrawings hereinafter. In the explanation made hereinafter, upper andlower sides are upper and lower sides in FIG. 1.

FIG. 1 is a view schematically showing one example of a fluid controldevice where a fixing device for a lower-stage member according to thepresent invention is used. The fluid control device (1) is of a typewhich is used in a semiconductor manufacturing device or the like, andincludes: a plurality of block joints (lower-stage members) (2), (3) ineach of which an upwardly-opened fluid path is formed, a plurality offluid control units (upper-stage members) (4), (5), (6), (7) in each ofwhich a downwardly-opened fluid path communicated with the fluid path ofthe block joint (2), (3) is formed; a plurality of seal portions (notshown in the drawing) which are interposed in abutting surfaces betweenthe fluid paths of the block joints (2), (3) and the fluid paths formedin bodies (4 a), (5 a), (6 a), (7 a) of the fluid control units (4),(5), (6), (7); a support member (9) which supports the plurality ofblock joints (2), (3); a plurality of bolts (10) by which the respectiveblock joints (2), (3) are mounted on the support member (9); and aplurality of bolts (20) by which the respective fluid control units (4),(5), (6), (7) are mounted on the block joints (2), (3).

As described later, in fixing the block joints (2), (3), spacers (12)and elastic members (21) are used in addition to the bolts (10).

FIG. 2 is a view showing the fixing device for a lower-stage memberaccording to the present invention in an enlarged manner. The fixingdevice for a lower-stage member is a device for fixing theabove-mentioned block joints (lower-stage members) (2) to the supportmember (9) by the bolt (10). As shown in FIG. 2, a bolt insertion hole(11) which is formed of a large diameter portion (11 a) having adiameter larger than a diameter of a bolt head portion (10 a) and asmall diameter portion (11 b) which is contiguously formed with thelarge diameter portion (11 a) below the large diameter portion (11 a)byway of a stepped portion (11 c) and has an intermediate diameterbetween the diameter of the bolt head portion (10 a) and a diameter of abolt shaft portion (10 b) is formed in the lower-stage member (2). Acylindrical spacer (12) provided with a flange (12 a) is fitted into thesmall diameter portion (11 b) of the bolt insertion hole, wherein thecylindrical spacer (12) has an inner diameter which is larger than thediameter of the bolt shaft portion (10 b), has a lower end which isreceived by the support member (9), and an upper end which receives thebolt head portion (10 a) in the inside of the large diameter portion (11a). Between a lower surface of the flange (12 a) of the spacer (12) andthe stepped portion (11 c), an annular elastic member (21) which biasesthe lower-stage member (2) downward (toward the support member (9)) isinterposed. The lower-stage members (2) each of which is provided withthe bolt insertion hole (11) and is arranged between the support member(9) and the upper-stage member (4), (5), (6), (7) are mounted on thesupport member (9) by the bolts (10). The spacer (12) may be a spacerhaving no flange (12 a). In this case, the elastic member (21) isinterposed between a lower surface of the bolt head portion (10 a) andthe stepped portion (11 c).

The fixing device for a lower-stage member according to the presentinvention is characterized by the shape of the elastic member (21). Theelastic member (21) is formed of an annular-shaped body made of rubberor a synthetic resin. With respect to the shape of the elastic member(21) before the upper-stage member (the body of the upper-stage memberis indicated by symbol (5 a)) shown in FIG. 2 is fixed to thelower-stage member (2), cutouts (21 a), (21 b) are formed on upper andlower portions of an outer peripheral surface of the elastic member (21)and hence, the elastic member (21) is elastically deformable by bending.

FIG. 6(A), and FIG. 6(B) are views for explaining a leveling function ofthe fixing device for a lower-stage member, and shows the positionalrelationship between the fixing device before the upper-stage member isfixed (FIG. 6(A)) and the fixing device after the upper-stage member isfixed (FIG. 6(B)). In FIG. 6(A), and FIG. 6(B), the bolt (10) fixes thespacer (12) to the support member (9) and hence, the bolt (10) and thespacer (12) are not movable relative to the support member (9). As shownin FIG. 6(A), the lower-stage member (2) receives a downward force fromthe spacer (12) by way of the elastic member (E) and hence, a lowersurface of the lower-stage member (2) is brought into contact with thesupport member (9) whereby the lower-stage member (2) is not movable. Anelastic force of the elastic member (E) made of rubber is smaller than aforce of a hand and hence, by applying an upward force to thelower-stage member (2) against the elastic force, as shown in FIG. 6(B),a user can lift up the lower-stage member (2) with his hand.Accordingly, when an upper surface of a certain lower-stage member (2)is low, by upwardly moving the lower-stage member (2) against theelastic force of the elastic member (E), an upper surface position ofthe lower-stage member (2) can be finely adjusted, that is, leveling canbe performed.

In a conventional fixing device shown in FIG. 7, a rubber washer (57) isused as the elastic member (E), and the rubber washer (57) has arectangular shape in cross section and is configured to be filled in aspace formed between a head portion (53 a) of a joint fixing bolt (53)and a stepped portion (54 c) of a bolt insertion hole (54). Accordingly,when the rubber washer (57) is used as the elastic member (E), a movableamount of the lower-stage member (2) at the time of fixing theupper-stage member is limited, and an elastic force (repulsive force) ofthe elastic member (E) is largely increased by upwardly moving thelower-stage member (2) and hence, there arises a drawback that theleveling operation becomes difficult.

The elastic member (21) of the fixing device for a lower-stage member ofthe present invention shown in FIG. 2 has an approximately lateral Tshape in cross section where the elastic member (21) is formed of avertical portion and a horizontal portion which extends radially outwardfrom a center portion of the vertical portion in the radial direction,and is formed in a shape where upper and lower corner portions of thevertical portion on an inner peripheral side are cut out. In otherwords, the elastic member (21) is formed of an annular body having anoctagonal shape in cross section formed by cutting out four corners of avertically-elongated rectangular shape as the reference, and the cutouts(21 a), (21 b) are formed on the upper portion and the lower portion ofthe outer peripheral surface of the annular body respectively.

The elastic member (21) of the fixing device for a lower-stage memberaccording to the present invention includes the cutouts (21 a), (21 b)and hence, the upper and lower end portions of the vertical portion canbe elastically deformed by bending in a state where cross-sectionalareas of the cutouts (21 a), (21 b) are decreased. FIG. 3(A) shows ashape of the elastic member (21) after the elastic member (21) isdeformed.

FIG. 3(B) shows a case where an elastic member (30) on which a cutout isnot formed is used for comparison. In FIG. 3(B), when the lower-stagemember (2) is made to move upward, a space formed between the flange (12a) of the spacer (12) and the stepped portion (11 c) is filled with theelastic member (30) at an early stage so that a repulsive force isincreased whereby the succeeding movement of the lower-stage member (2)in the upward direction becomes difficult. Accordingly, there exists apossibility that a gap (G) remains between the body (5 a) of theupper-stage member and the lower-stage member (2).

To the contrary, in the elastic member (21) shown in FIG. 2, as shown inFIG. 3(A), a gap between the body (5 a) of the upper-stage member andthe lower-stage member (2) can be eliminated and hence, the elasticmember (21) is in a state where the elastic member (21) can be furtherelastically deformed by bending from such a state whereby a levelingoperation can be performed extremely easily. Further, since the elasticmember (21) can be elastically deformed by bending, the fixing device ofthe present invention is advantageous compared to the prior art alsowith respect to a vibration absorbing effect.

The above-mentioned example is only one example, and the shape of theelastic member can be changed variously. For example, the number ofcutouts may be two, the position where the cutout is formed may bechanged or the number of cutouts may be one or three or more. Theelastic member (21) having two cutouts is shown in FIG. 4(A), FIG. 4(B),FIG. 4(C) and FIG. 4(D), while the elastic member having one or three ormore cutouts is shown in FIG. 5(A), FIG. 5(B), and FIG. 5(C).

The elastic member (21) shown in FIG. 4(A) is the same elastic member(21) shown in FIG. 2. While the elastic member shown in FIG. 4(A) isprovided with the cutouts (21 a), (21 b) on two portions, that is, anupper portion and a lower portion of an outer peripheral surface of theelastic member (21) respectively, the elastic member (22) shown in FIG.4(B) is provided with the cutouts (22 a), (22 b) on two portions, thatis, an upper portion and a lower portion of an inner peripheral surfaceof the elastic member (22) respectively (cross-sectional shape beingapproximately lateral T shape with inside and outside reversed).

The elastic member (23) shown in FIG. 4(C) is provided with cutouts (23a), (23 b) on two portions in total such that the cutout (23 a) isformed on one portion of a vertical center portion of an innerperipheral surface of the elastic member (23) and the cutout (23 b) isformed on one portion of a vertical center portion of an outerperipheral surface of the elastic member (23). Cross-sectional shapes ofthe cutouts (23 a), (23 b) are an approximately rectangular shape in thesame manner as the above. Accordingly, the elastic member (23) has anapproximately I-shaped cross-sectional shape. The elastic member (24)shown in FIG. 4(D) is, in the same manner as the elastic member (23)shown in FIG. 4(C), provided with cutouts (24 a), (24 b) on two portionsin total such that the cutout (24 a) is formed on one portion of avertical center portion of an inner peripheral surface of the elasticmember (24) and the cutout (24 b) is formed on one portion of a verticalcenter portion of an outer peripheral surface of the elastic member(24). By forming cross-sectional shapes of the cutouts (24 a), (24 b)into an approximately triangular shape, the elastic member (24) has anapproximately Z-shaped cross-sectional shape.

The elastic member (25) shown in FIG. 5(A) is provided with a cutout (25a) only one portion of a vertical center portion of an inner peripheralsurface of the elastic member (25), and the elastic member (25) has anapproximately C-shaped or approximately U-shaped cross-sectional shape.The cross-sectional shape of the cutout (25 a) may be formed into arectangular shape, a triangular shape, an arcuate shape or the like incross section. Although not shown in the drawing, the similar cutout (25a) may be formed on an outer peripheral surface of the elastic member(25) instead of the inner peripheral surface of the elastic member (25).

The elastic member (26) shown in FIG. 5(B) is provided with cutouts (26a), (26 b), (26 c) on three portions in total such that the cutout (26a) is formed on one portion of an upper portion of an inner peripheralsurface of the elastic member (26), the cutout (26 b) is formed on oneportion of a center portion of the inner peripheral surface of theelastic member (26), and the cutout (26 c) is formed on one portion of alower portion of the inner peripheral surface of the elastic member(26). That is, the elastic member (26) has an approximately lateralΠ-shaped cross-sectional shape. Although not shown in the drawing,similar cutouts (26 a), (26 b), (26 c) may be formed on an outerperipheral surface of the elastic member (26) instead of the innerperipheral surface of the elastic member (26).

The elastic member (27) shown in FIG. 5(C) is provided with cutouts (27a), (27 b), (27 c), (27 d) on four portions in total such that thecutout (27 a) is formed on one portion of a vertical center portion ofan inner peripheral surface of the elastic member (27), the cutout (27b) is formed on one portion of a vertical center portion of an outerperipheral surface of the elastic member (27), the cutout (27 c) isformed on one portion of a center portion of an upper surface of theelastic member (27), and the cutout (27 d) is formed on one portion of acenter portion of a lower surface of the elastic member (27).

All of the elastic members (21), (22), (23), (24), (25), (26), (27)shown in FIG. 4(A), FIG. 4(B), FIG. 4(C) and FIG. 4(D) and FIG. 5(A),FIG. 5(B), and FIG. 5(C) are respectively formed of an annular body madeof rubber or a synthetic resin, and the cutout (21 a), (21 b), (22 a),(22 b), (23 a), (23 b), (24 a), (24 b), (25 a), (26 a), (26 b), (26 c),(27 a), (27 b), (27 c), (27 d) which enable the elastic deformation bybending of the elastic member (21), (22), (23), (24), (25), (26), (27)when a force in the vertical direction is applied is formed on at leastone portion of the outer peripheral surface, the inner peripheralsurface, the upper surface, and the lower surface of the elastic member.Accordingly, a leveling operation for making upper surfaces of thelower-stage members (2) coplanar can be easily performed, and avibration absorbing effect of the elastic member (21), (22), (23), (24),(25), (26), (27) can be further enhanced.

INDUSTRIAL APPLICABILITY

The fixing device for a lower-stage member according to the presentinvention is used in a fluid control device which is assembled such thata fluid control unit is fixed in a straddling manner over a plurality ofjoints. According to the present invention, it is possible to acquire afluid control device which can easily perform a leveling operation formaking upper surfaces of lower stage members coplanar, and can alsofurther enhance a vibration absorbing effect of the elastic member.

1. A fixing device for a lower-stage member which fixes the lower-stagemember arranged between a support member and an upper-stage member andprovided with a bolt insertion hole to a support member by a bolt, thefixing device comprising: the bolt insertion hole formed in thelower-stage member and provided with a large-diameter portion having adiameter larger than a diameter of a bolt head portion and asmall-diameter portion which is contiguously formed with thelarge-diameter portion below the large-diameter portion by way of astepped portion and has an intermediate diameter between the diameter ofthe bolt head portion and a diameter of a bolt shaft portion, acylindrical spacer which has an inner diameter larger than the diameterof the bolt shaft portion, has a lower end thereof received by thesupport member and has an upper end thereof disposed in the inside ofthe large-diameter portion, the spacer being fitted into thesmall-diameter portion of the bolt insertion hole, and an elastic memberwhich biases the lower-stage member toward the support member and whichis interposed between the bolt head portion and the stepped portion,wherein the lower-stage member is moved upwardly against an elasticforce of the elastic member, the elastic member is formed of an annularbody made of rubber or a synthetic resin and arranged between a lowersurface of a flange mounted on an upper end portion of the spacer and astepped portion, an upper portion, a lower portion and a center portionof an inner peripheral surface and an outer peripheral surface of theelastic member respectively comprise a cutout, a cross-sectional shapeof the elastic member before the cutout is formed is an octagonal shapewhich is formed by cutting four corners of a rectangular shape elongatedin a vertical direction, a gap between the upper-stage member and thelower-stage member can be eliminated, and the elastic member is in astate in which the elastic member can be further elastically deformed bybending from the state. 2-9. (canceled)
 10. A fluid control devicecomprising: a plurality of block joints in each of which a fluid pathopening upward is formed; a plurality of fluid control units in each ofwhich a fluid path communicated with the fluid path of the block jointand opening downward is formed; a plurality of seal portions which areinterposed on abutting surfaces between the fluid paths of the blockjoints and the fluid paths of the fluid control units; a support memberfor supporting the plurality of block joints; a plurality of bolts formounting the respective block joints to the support member; and aplurality of bolts for mounting the respective fluid control units tothe block joints, wherein the block joint constitutes a lower-stagemember, and the block joint is mounted on the support member by any oneof the above-mentioned fixing devices for a lower-stage member describedin claim
 1. 11. The fixing device for a lower-stage member according toclaim 1, wherein the cutout has a rectangular cross-sectional shape andis formed on a vertical center portion of the inner peripheral surfaceand a vertical center portion of the outer peripheral surface of theelastic member respectively.
 12. The fixing device for a lower-stagemember according to claim 1, wherein the cutout has a triangularcross-sectional shape and is formed on a vertical center portion of theinner peripheral surface and a vertical center portion of the outerperipheral surface of the elastic member respectively so that thecross-sectional shape of the elastic member is in a Z-shape.
 13. Thefixing device for a lower-stage member according to claim 1, wherein thecutout has a rectangular cross-sectional shape and is formed on avertical center portion of the inner peripheral surface, a verticalcenter portion of the outer peripheral surface, a center portion of anupper surface, and a center portion of a lower surface of the elasticmember respectively.